As a disposable diaper mainly used for, e.g., infants and toddlers, a so-called open-type disposable diaper has been provided, in which fastening tapes for fixation are provided at side flaps in a rear waistline region.
The known structure for such an open-type disposable diaper in which the stiffness of the front ends of the fastening tapes is set smaller than that of the base ends of the fastening tapes (for example, Patent Literature 1, FIG. 1).